This invention relates to a method and system for propagating growing plants and seeds by maintaining a supply of plant nutrients and water to the plants or seeds. More particularly, this invention relates to a method for propagating the growth of plants or seeds while preventing formation of algae and while minimizing evaporation of water.
Conventional plant propagators utilize a flat bed or storage trays which may be waterproof or may comprise a perforated tank. The tanks are provided with delivery pipes fitted with nozzles for delivering the nutrients. The delivery pipes of the individual tanks may be isolated from the entire supply system through control and stopcocks. Tanks equipped in this way are filled with a sand layer whose surface is leveled. By opening the stopcocks, the tanks are filled until the sandbeds are saturated with water but without the water level rising above the sand layer surface. The plants or seeds are supplied with the moisture either directly or through holes provided in the bottoms of pots or other vessels. The use of container plant production of crops is of increasing importance due to rising land values and labor cost for producing field-grown stock. Container plant production offers advantages over fieldgrown stock including: extended sales in planting seasons, development of attractive sales packages, greater transportability, beter control of environmental and cultural factors and more efficient use of labor, production and sales areas.
Growing plants in containers, however, presents special problems of watering and fertilizing not experienced in field production. Frequent excess overhead irrigation, besides being inefficient, can cause severe leaching of nutrients from the containers. This frequently results in pollution of nearby streams caused by the excess run-off from the plant growing areas.
The use of a sand layer, also, is disadvantageous since the sand surface becomes covered with algae far too quickly. This results in a reduction in the transmission of water or nutrient liquid into the plant containers until finally the supply is stopped altogether. Although the algae can be destroyed by conventional chemical preparations, it has been shown that the development of plants is adversely affected by such preparations. In addition, considerable expense is involved with such preparations.
It has been proposed in U.S. Pat. No. 4,001,968 to utilize a plant growing system where water is supplied to a layer of sand, positioned between two layers of plastic sheet wherein the top layer is perforated with a multiplicity of small holes through which water moves by capillary action. A container housing soil and a plant and having a perforated bottom is placed upon the perforated plastic sheet so that water passing through the holes in the sheet supplies the plant with water and nutrients. While this system substantially reduces the amount of water loss by way of evaporation, its use is undesirable since the small holes in the top plastic sheet expose the wet sand to light and air thereby promoting undesirable algae formation.
It would be highly desirable to provide a system for growing plants which minimizes water loss since water is expensive and in many cases only limitedly available. In addition, it would be highly desirable to provide such a plant growing system which eliminated excess water run-off, thereby preventing pollution of the surrounding environment. In addition, it would be desirable to provide such a system which eliminates undesirable algae growth.